Which of the following is an example of graywater?

Graywater refers to wastewater that has been used in household activities but can still be recycled for certain non-potable uses. Examples of graywater sources typically include water from baths, showers, bathroom sinks, washing machines, and dishwashers.

Untreated laundry water fits the definition of graywater because it is wastewater generated from washing clothes. This water can often be reused for irrigation or toilet flushing, depending on the local regulations and treatment processes.

In contrast, rainwater collected from roofs is considered rainwater harvesting rather than graywater, as it has not been used in household activities. Water from kitchen sinks can sometimes be classified as food waste or blackwater if it contains substantial food particles, which distinguishes it from graywater. Stormwater runoff is another separate category, dealing with water that flows over surfaces and can carry pollutants.

Therefore, untreated laundry water is the correct identification of graywater because it is generated from a household process and has the potential for reuse in ways that promote water efficiency.